Upconversion nanoparticles (UCNPs) can effectively assist solar cells in utilizing near infrared through the anti-Stokes’ emission mechanism. We incorporate UCNPs, for the first time, into the mesoporous TiO₂ of dye-sensitized solar cells (DSSCs) in a low-temperature fabrication process. The mesoporous TiO₂ is designed as a two-layer structure, where the lower layer is prepared from reactive anatase TiO₂ chelated by acetic acid (h-TAc). The UCNP incorporation into the lower layer displays a significant improvement in photovoltaic performance. For an optimized UCNP incorporation, the power conversion efficiency (PCE) of the DSSCs can increase from 6.49 to 7.98%, an enhancement of 23%, further exceeding most of the improvement on low-temperature fabricated DSSCs reported in the literature. The enhanced PCE may be ascribed to the increase of photocurrent. We find that the hydrophobic UCNPs reveal better enhancement than hydrophilic UCNPs due to the prevention from the electrolyte penetration. However, the hydrophobic UCNP incorporation may cause the cracking of the mesoporous TiO₂ layer. The strong bonding ability of h-TAc effectively alleviates the cracking issue.

上转换纳米粒子（UCNPs）可以通过反斯托克斯发射机制有效地帮助太阳能电池利用近红外。我们首次在低温制造过程中将 UCNP 掺入染料敏化太阳能电池 (DSSC)的介孔 TiO ₂中。介孔 TiO ₂设计为两层结构，其中下层由反应性锐钛矿型 TiO ₂制备被乙酸螯合（h-TAc）。UCNP 并入下层显示出光伏性能的显着改善。对于优化的 UCNP 掺入，DSSCs 的功率转换效率 (PCE) 可以从 6.49% 增加到 7.98%，提高了 23%，进一步超过了文献中报道的低温制造 DSSCs 的大部分改进。增强的 PCE 可能归因于光电流的增加。我们发现由于防止电解质渗透，疏水性 UCNPs 比亲水性 UCNPs 显示出更好的增强。然而，疏水性UCNP的掺入可能导致介孔TiO ₂层开裂。h-TAc 的强键合能力有效地缓解了开裂问题。